A hammering device according to the above preamble is previously known from published Finnish applications FI-20100161 and FI-20120026 where the object to be hammered can be gripped with side grip and hammering force is transferred to the object via jaw bars of the gripping jaws. In these solutions vibrator device has been placed essentially deviating from the vertical line which goes via longish object to be hammered and which would be the most effective hammering line. This deviation causes loads to the construction of the hammering device and also reduces the hammering effect.